Question

An animal having pentadactyl limbs without claws belong to the class
(a) Amphibia
(b) Reptilia
(c) Aves
(d) Mammalia

Answer 1

Hint: A limb with five digits is called a pentadactyl limb. It is characteristic of tetrapod vertebrates. The human hand or foot is an example of a pentadactyl limb. It is found in many amphibia, reptiles, birds, and animals. This allows us to interpret that many vertebrates are descended from the same common ancestor.

Complete answer:
An animal having pentadactyl limbs without claws belongs to the class amphibia. The pentadactyl limbs exist in animals from dolphins to the horse to the bat and each animal uses the same limb in different ways. Each pentadactyl limb has the same basic structure of five digits. The amphibian's body has two pairs of limbs. The forelimbs have four toes whereas the hindlimbs have five toes and toes are without claws.
Additional information:
- Amphibians are non- scaly moist, slimy skin vertebrates with the five- digit limb.
- They have three- chambered hearts. They use gills or lungs for breathing.
- Amphibians are cold- blooded, poikilothermic, and found both in water and land.
- They are unisexual, oviparous having external fertilization.
- Examples: salamander, toad. Common frog, tree frog, etc.
- Amphibians’ limbs are the least specialized.
- These are pentadactyl without claws or nails.
So, the correct answer is ‘amphibia’.

Note:
- Pentadactyl limb is evolved from the paired fins of primitive fish as an adaptation to locomotion on land and is not found in modern fish.
- The limb has three parts: the upper arm or thigh containing one long bone, the forearm, or shank - containing two long bones and the hand or foot, which contains No.of small bones.
- This basic design is modified in many species, according to the function of the limb.